Study On Structures And Properties Of GF/PET Composites In Additional Shear Field

By a set of self-making and controllable special equipment and a sheet die, we build controllable shear field and prepare GF/PP sheets, and study regularities of structure and properties of glass fiber reinforced PP composite. Controllable shear equipment sequentially is connected with fore-end of single screw extruder. Firstly, GF/PP pellet is prepared by double-screw extrude, then plasticize GF/PP pellet, next prepare sheet, finally, cut sample from sheet and analyze its structure and properties. By testing mechanical properties, we can studied on shear field change, different kind of matrix and glass fiber, different glass fiber treatment influencing on mechanical properties of GF/PP composite; The effect of modified matrix and different glass fiber treatment on rheological behaviors were studied by rheological tests; Interfacial structure and crystal characters of GF/PP composite and different glass fiber treatment were analyzed and through DSC, SEM and IR spectroscopy testing. The main conclusions of this study were shown as follows:(1)The controllable shear field was generated by adjusting the rotating speed for the mandrel in the shear equipment barrel. By which we can build adjustable shear field and plasticize, and provide dynamic analog conditions for studying interface of GF/PP composite.(2)Different glass fiber treatments have great effect on interfacial structure, broken mode, rheological behaviors, crystal characters of GF/PP composite. Because of reacting between coupling agent and interface of glass fiber, mechanical properties will have obviously improve. Under shear field conditions, maximum value of breaking strengthen appears in 250 s-1, if number of turns was continuously increased, it is happen interfacial debond, and mechanical properties will bad.(3)Under additional shear field, interface of glass fiber is treated by polymeric filmogen and coupling. Results show that interfacial bonding of glass fiber reinforced PP has obviously improve, and treating glass fiber has stronger heterogeneous nucleation, more perfect crystals. Which result in conspicuously increasing mechanical properties of GF/PP. As far as GF/PP is concerned, the effect of POE filmogen and KH550 is the best, PU and KH550is the second, K-resin and KH550 is the worst.(4)Comparing untreated glass fiber with treated glass fiber, they have the same of the regularity of tensile-strength with vary of number of turns. With increasing number of turns, the curve of both breaking strength is parabolic, the effect of silane coupling and polymeric filmogen reinforced composite is best, only silane coupling treating glass fiber is second, untreated glass fiber is worse.(5)Compared composite of glass fiber reinforced homopolymer and copolymer of polypropylene, when matrix is copolymer, its reinforcing effect is better than homopolymer.(6)Under additional shear field conditions, modified polypropylene by MAH-g-PP, which increases interfacial interwinding of GF/PP, and increases crystallinity , strength of GF/PP is improved , at the same time, apparent viscosity is apparently decreased.(7)The improving effect has related with type of non alkali glass, the more thin diameter of glass fiber, the more high strength.(8)Glass fiber can reduce apparent viscosity of composite, the more flexible of filmogen of glass fiber interface, the more obviously decreasing apparent viscosity.